This invention relates to a blade for ice skates, particularly to a blade having a plurality of alternately facing oblique triangular surfaces on the top edge thereof.
Most skates comprise a shoe portion for containing a skater's foot and a base portion attached to the lower surface of the shoe portion for sliding on ice. The base portion further comprises a blade whose lower edge is supposed to slide on the ice, and a plastic material jointed to the upper part of the blade. Since attachability of plastic material to the upper part of the blade is not high due to the plane contact surface therebetween, the plastic material is inherently subject to detachment from the blade. In order to mitigate the easy detachment problem, DE Pat. No. 3,326,154 to Tessari disclosed a steel blade whose upper edge is provided with cut-outs having either the same direction or the opposite direction on the two sides of the center line. Then, shrinkable plastics are applied by injection molding on the upper part of the blade. This ensures a high strength of the joint between plastics and metal blade. For the same purposes, U.S. Pat. No. 3,212,786 to Florjancic et al disclosed that the blade is provided with a plurality of elongated indentations evenly spaced in the longitudinal direction of the blade alternatively from opposite side faces into the blade so as to form opposite indentation an elongated transverse projection. During molding of the frame means onto the blade, the indentations are completely filled and the lateral projections completely embedded in the plastic material of the frame means. The indentations and projections enhance the jointability between the blade and the frame means. Nevertheless, although these techniques have solved the detachment problem, they introduce new problems. Referring to FIG. 5, a sectional view taken along the inclined slot or cut-out of Tessari, it can be seen that the multiplicity of areas A are the only areas on which normal stress is applied by the contacting plastic material as the skate is accelerated or decelerated. Therefore, the contacting plastic material is subject to deformation as applied on reactive stress. This disenhances the jointability between the blade and the plastic frame, and thus the portion of plastic material in contact with the side faces of the blade is subject to dislocation. Referring to FIG. 6, a sectional view taken from a vertical plane to the blade of Florjancic et al., it can be seen that areas B have normal stress applied thereto. Since area B is not large enough, the same result of dislocation will occur with the skate disclosed in Florjancic et al. Furthermore, the indentations comparatively complicate the manufacture.